It would be nice if we could create bookmarks that can set layers and base maps on the 2D map (on Map Viewer/Experience Builder), similar to the ability of the slide manager on ArcGIS Scene Viewer. This is a useful feature because users can define different base maps and layer representations when creating bookmarks. This feature is a great way to allow users to users to present 2D maps to tell interactive stories with the data in your 2D maps in a more engaging way. It can also be used as a starting point when you open the map again too.
Slide Manager in ArcGIS Scene Viewer (3D Map)
ฺBookmark on 2D Map (Users cannot define different base maps when creating bookmarks.)